Description of Problem:
I found this while trying to add an attachment to a bugzilla.  While browsing, I
visited a directory that had many files in it, but the one I wanted was the last
one visible in the dialog (but not the last file in the directory).  When I went
to double-click on it, the first click caused the list to scroll up one line,
and so did the second click.  Double-clicking on files in the middle of the list
works fine.

Version-Release number of selected component (if applicable):
mozilla-1.0.1-10


How Reproducible:
Very

Steps to Reproduce:
1. start to attach a file to a bugzilla
2. browse to a directory that has lots of files in it
3. try to double-click on the last file visible in the list (but not the last
file in the directory)

Actual Results:
list scrolls up two lines

Expected Results:
double-clicking should select the desired file

Additional Information:
screen resolution 1152x864
stock fonts